93 lines
1.4 KiB
Go
93 lines
1.4 KiB
Go
package cid
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import (
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mh "github.com/multiformats/go-multihash"
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)
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type Format interface {
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Sum(data []byte) (*Cid, error)
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GetCodec() uint64
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WithCodec(uint64) Format
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}
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type FormatV0 struct{}
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type FormatV1 struct {
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Codec uint64
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HashFun uint64
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HashLen int // HashLen <= 0 means the default length
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}
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func PrefixToFormat(p Prefix) Format {
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if p.Version == 0 {
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return FormatV0{}
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}
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mhLen := p.MhLength
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if p.MhType == mh.ID {
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mhLen = 0
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}
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if mhLen < 0 {
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mhLen = 0
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}
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return FormatV1{
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Codec: p.Codec,
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HashFun: p.MhType,
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HashLen: mhLen,
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}
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}
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func (p Prefix) GetCodec() uint64 {
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return p.Codec
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}
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func (p Prefix) WithCodec(c uint64) Format {
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if c == p.Codec {
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return p
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}
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p.Codec = c
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if c != DagProtobuf {
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p.Version = 1
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}
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return p
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}
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func (p FormatV0) Sum(data []byte) (*Cid, error) {
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hash, err := mh.Sum(data, mh.SHA2_256, -1)
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if err != nil {
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return nil, err
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}
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return NewCidV0(hash), nil
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}
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func (p FormatV0) GetCodec() uint64 {
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return DagProtobuf
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}
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func (p FormatV0) WithCodec(c uint64) Format {
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if c == DagProtobuf {
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return p
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}
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return FormatV1{Codec: c, HashFun: mh.SHA2_256}
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}
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func (p FormatV1) Sum(data []byte) (*Cid, error) {
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mhLen := p.HashLen
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if mhLen <= 0 {
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mhLen = -1
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}
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hash, err := mh.Sum(data, p.HashFun, mhLen)
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if err != nil {
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return nil, err
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}
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return NewCidV1(p.Codec, hash), nil
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}
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func (p FormatV1) GetCodec() uint64 {
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return p.Codec
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}
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func (p FormatV1) WithCodec(c uint64) Format {
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p.Codec = c
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return p
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}
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